A forming device is used for enabling a to-be-formed piece to be formed into a plurality of feature structures. The forming device comprises a mold unit, a cooling unit, a gas-cooling unit and a gas escape unit; the mold unit is provided with a mold cavity in a surrounding mode and a plurality of feature sections not making contact with the to-be-formed piece; the cooling unit comprises a plurality of cooling water channels formed in the mold unit; and the gas-cooling unit comprises a plurality of blowing openings formed in the mold unit in the mode of facing the feature sections and communicating with the mold cavity, and a plurality of cooling gas passages connected with the blowing openings correspondingly and used for supplying cooling gas. The cooling gas can be blown into the mold cavity through the blowing openings so as to cool the part, not making contact with the mold unit, of the to-be-formed piece, accordingly, the uniform cooling speed can be achieved, the large wall thickness difference of finished products is avoided, and the yield rate of the products is increased.